[stdlib] Provisional c[...] syntax while we await language features

apple · May 13, 2017 · 4dee6ea · 4dee6ea
1 parent 5d034a2
commit 4dee6ea
Show file tree

Hide file tree

Showing 4 changed files with 38 additions and 21 deletions.
diff --git a/stdlib/private/StdlibCollectionUnittest/CheckCollectionType.swift.gyb b/stdlib/private/StdlibCollectionUnittest/CheckCollectionType.swift.gyb
@@ -1041,7 +1041,7 @@ extension TestSuite {
     self.test("\(testNamePrefix).removeFirst()/slice/semantics") {
       for test in removeFirstTests.filter({ $0.numberToRemove == 1 }) {
         let c = makeWrappedCollection(test.collection.map(OpaqueValue.init))
-        var slice = c[c.startIndex..<c.endIndex]
+        var slice = c[...]
         let survivingIndices = _allIndices(
           into: slice,
           in: slice.index(after: slice.startIndex)..<slice.endIndex)
@@ -1081,7 +1081,7 @@ extension TestSuite {
     self.test("\(testNamePrefix).removeFirst(n: Int)/slice/semantics") {
       for test in removeFirstTests {
         let c = makeWrappedCollection(test.collection.map(OpaqueValue.init))
-        var slice = c[c.startIndex..<c.endIndex]
+        var slice = c[...]
         let survivingIndices = _allIndices(
           into: slice,
           in: slice.index(
@@ -1140,7 +1140,7 @@ extension TestSuite {
       // This can just reuse the test data for removeFirst()
       for test in removeFirstTests.filter({ $0.numberToRemove == 1 }) {
         let c = makeWrappedCollection(test.collection.map(OpaqueValue.init))
-        var slice = c[c.startIndex..<c.endIndex]
+        var slice = c[...]
         let survivingIndices = _allIndices(
           into: slice,
           in: slice.index(after: slice.startIndex)..<slice.endIndex)
@@ -1236,7 +1236,7 @@ extension TestSuite {
     self.test("\(testNamePrefix).removeLast()/slice/semantics") {
       for test in removeLastTests.filter({ $0.numberToRemove == 1 }) {
         let c = makeWrappedCollection(test.collection)
-        var slice = c[c.startIndex..<c.endIndex]
+        var slice = c[...]
         let survivingIndices = _allIndices(
             into: slice,
           in: slice.startIndex
@@ -1281,7 +1281,7 @@ extension TestSuite {
     self.test("\(testNamePrefix).removeLast(n: Int)/slice/semantics") {
       for test in removeLastTests {
         let c = makeWrappedCollection(test.collection)
-        var slice = c[c.startIndex..<c.endIndex]
+        var slice = c[...]
         let survivingIndices = _allIndices(
           into: slice,
           in: slice.startIndex
@@ -1342,7 +1342,7 @@ extension TestSuite {
       // This can just reuse the test data for removeLast()
       for test in removeLastTests.filter({ $0.numberToRemove == 1 }) {
         let c = makeWrappedCollection(test.collection)
-        var slice = c[c.startIndex..<c.endIndex]
+        var slice = c[...]
         let survivingIndices = _allIndices(
           into: slice,
           in: slice.startIndex

diff --git a/stdlib/private/StdlibCollectionUnittest/CheckMutableCollectionType.swift.gyb b/stdlib/private/StdlibCollectionUnittest/CheckMutableCollectionType.swift.gyb
@@ -260,8 +260,7 @@ self.test("\(testNamePrefix).subscript(_: Range)/Set/semantics") {
 
       let newElements = makeWrappedCollection(
         test.expected.map { OpaqueValue($0.value + 90000) })
-      c[test.bounds(in: c)] =
-        newElements[newElements.startIndex..<newElements.endIndex]
+      c[test.bounds(in: c)] = newElements[...]
 
       // FIXME: improve checkForwardCollection to check the SubSequence type.
       /*
@@ -303,17 +302,15 @@ if isFixedLengthCollection {
     let newElements = makeWrappedCollection([ 91010, 92020, 93030, 94040 ].map(OpaqueValue.init))
 
     expectCrashLater()
-    c[c.startIndex..<c.endIndex] =
-      newElements[newElements.startIndex..<newElements.endIndex]
+    c[...] = newElements[...]
   }
 
   self.test("\(testNamePrefix).subscript(_: Range)/Set/SmallerRange") {
     var c = makeWrappedCollection([ 1010, 2020, 3030 ].map(OpaqueValue.init))
     let newElements = makeWrappedCollection([ 91010, 92020 ].map(OpaqueValue.init))
 
     expectCrashLater()
-    c[c.startIndex..<c.endIndex] =
-      newElements[newElements.startIndex..<newElements.endIndex]
+    c[...] = newElements[...]
   }
 } else {
   self.test("\(testNamePrefix).subscript(_: Range)/Set/DifferentlySizedRange") {
@@ -322,8 +319,7 @@ if isFixedLengthCollection {
       let newElements = makeWrappedCollection(test.newElements)
       let rangeToReplace = test.rangeSelection.range(in: c)
 
-      c[rangeToReplace] =
-        newElements[newElements.startIndex..<newElements.endIndex]
+      c[rangeToReplace] = newElements[...]
 
       expectEqualSequence(
         test.expected,
@@ -367,8 +363,7 @@ if resiliencyChecks.subscriptRangeOnOutOfBoundsRangesBehavior != .none {
             let newValues = makeWrappedCollection(
               elements[i..<j].map { OpaqueValue($0.value + 90000) }
             )
-            slice[subSliceStartIndex..<subSliceEndIndex]
-              = newValues[newValues.startIndex..<newValues.endIndex]
+            slice[subSliceStartIndex..<subSliceEndIndex] = newValues[...]
             let subSlice = slice[subSliceStartIndex..<subSliceEndIndex]
             for (k, index) in subSlice.indices.enumerated() {
               expectEqual(
@@ -382,8 +377,7 @@ if resiliencyChecks.subscriptRangeOnOutOfBoundsRangesBehavior != .none {
                 extractValue(subSlice[index]).value)
             }
             let oldValues = makeWrappedCollection(Array(elements[i..<j]))
-            slice[subSliceStartIndex..<subSliceEndIndex]
-              = oldValues[oldValues.startIndex..<oldValues.endIndex]
+            slice[subSliceStartIndex..<subSliceEndIndex] = oldValues[...]
           }
         }
       }
@@ -437,7 +431,7 @@ if resiliencyChecks.subscriptRangeOnOutOfBoundsRangesBehavior != .none {
     let count: Int = numericCast(
       base.distance(from: bounds.lowerBound, to: bounds.upperBound))
     let newValues = makeWrappedCollection(Array(elements[0..<count]))
-    let newSlice = newValues[newValues.startIndex..<newValues.endIndex]
+    let newSlice = newValues[...]
 
     expectCrashLater()
     slice[bounds] = newSlice

diff --git a/stdlib/public/core/Range.swift.gyb b/stdlib/public/core/Range.swift.gyb
@@ -929,12 +929,26 @@ extension Strideable where Stride: SignedInteger {
   }
 }
 
+// FIXME: replace this with a computed var named `...` when the language makes
+// that possible.
+public enum UnboundedRange_ {
+  public static postfix func ... (_: UnboundedRange_) -> () {
+    fatalError("uncallable")
+  }
+}
+public typealias UnboundedRange = (UnboundedRange_)->()
+
 extension _Indexable {
   @_inlineable
   public subscript<R: RangeExpression>(r: R)
   -> SubSequence where R.Bound == Index {
     return self[r.relative(to: self)]
   }
+
+  @_inlineable
+  public subscript(x: UnboundedRange) -> SubSequence {
+    return self[startIndex...]
+  }
 }
 extension _MutableIndexable {
   @_inlineable
@@ -947,6 +961,15 @@ extension _MutableIndexable {
       self[r.relative(to: self)] = newValue
     }
   }
+
+  public subscript(x: UnboundedRange) -> SubSequence {
+    get {
+      return self[startIndex...]
+    }
+    set {
+      self[startIndex...] = newValue
+    }
+  }
 }
 
 // swift-3-indexing-model: this is not really a proper rename

diff --git a/test/stdlib/RangeDiagnostics.swift b/test/stdlib/RangeDiagnostics.swift
@@ -302,8 +302,8 @@ func disallowSubscriptingOnIntegers() {
     r1[0...4]   // expected-error {{ambiguous use of 'subscript'}}
     r2[0...4]   // expected-error {{ambiguous reference to member 'subscript'}}
     r3[0...4]   // expected-error {{ambiguous reference to member 'subscript'}} 
-    (10...100)[0...4] // expected-error {{cannot subscript a value of type 'CountableClosedRange<_>' with an index of type 'CountableClosedRange<_>'}} expected-note {{overloads for 'subscript' exist with these partially matching parameter lists: (ClosedRangeIndex<Bound>), (Range<ClosedRangeIndex<Bound>>), (Range<Self.Index>), (R), (ClosedRange<Self.Index>), (CountableRange<Self.Index>), (CountableClosedRange<Self.Index>)}}
-    (UInt(10)...100)[0...4] // expected-error {{cannot subscript a value of type 'CountableClosedRange<_>' with an index of type 'CountableClosedRange<_>'}} expected-note {{overloads for 'subscript' exist with these partially matching parameter lists: (ClosedRangeIndex<Bound>), (Range<ClosedRangeIndex<Bound>>), (Range<Self.Index>), (R), (ClosedRange<Self.Index>), (CountableRange<Self.Index>), (CountableClosedRange<Self.Index>)}}
+    (10...100)[0...4] // expected-error {{cannot subscript a value of type 'CountableClosedRange<_>' with an index of type 'CountableClosedRange<_>'}} expected-note {{overloads for 'subscript' exist with these partially matching parameter lists: (ClosedRangeIndex<Bound>), (Range<ClosedRangeIndex<Bound>>), (Range<Self.Index>), (R), ((UnboundedRange_) -> ()), (ClosedRange<Self.Index>), (CountableRange<Self.Index>), (CountableClosedRange<Self.Index>)}}
+    (UInt(10)...100)[0...4] // expected-error {{cannot subscript a value of type 'CountableClosedRange<_>' with an index of type 'CountableClosedRange<_>'}} expected-note {{overloads for 'subscript' exist with these partially matching parameter lists: (ClosedRangeIndex<Bound>), (Range<ClosedRangeIndex<Bound>>), (Range<Self.Index>), (R), ((UnboundedRange_) -> ()), (ClosedRange<Self.Index>), (CountableRange<Self.Index>), (CountableClosedRange<Self.Index>)}}
 
     r0[r0]      // expected-error {{ambiguous use of 'subscript'}}
     r0[r1]      // expected-error {{ambiguous subscript with base type 'CountableRange<Int>' and index type 'CountableRange<UInt>'}}